This invention relates to the art of medical electronics, and more particularly to a new and improved patient signalling system.
One area of use of the present invention is in enabling patients to sound an alarm or call for help, although the principles of the present invention can be variously applied. Patients suffering from multiple sclerosis, amyotrophic sclerosis, similar neurological disorders and strokes often are afflicted with loss of speech and limited capability of movement, and usually such patients are unable to push buttons or manipulate conventional switches on existing patient alarm and calling systems. Accordingly, it would be highly desirable to provide a patient alarm or calling system which is activated in a manner requiring the slightest expenditure of effort on the part of the patient.
In providing such a patient-activated alarm or calling system a number of requirements must be considered. There must be electrical compatibility between the system and electrically-operated relays, solid state relays or optical isolators and the like at the inputs of intercom devices or other appliances which the system is to signal or cause operation thereof. Also, typically such intercom devices and other appliances are a.c. operated, and it would be highly desirable to eliminate the possibility of any shock hazard to the patient so that the system can be utilized also in intensive care and cardiac care environments.